Your odds of “making it to the top” might be better than you think, although it’s tough to stay on top once you get there.

According to research from Cornell University, over 50 percent of Americans find themselves among the top 10 percent of income-earners for at least one year during their working lives. Over 11 percent of Americans will be counted among the top 1 percent of income-earners (i.e., people making at minimum $332,000) for at least one year.

How is this possible? Simple: the rate of turnover in these groups is extremely high.

Just how high? Some 94 percent of Americans who reach “top 1 percent” income status will enjoy it for only a single year. Approximately 99 percent will lose their “top 1 percent” status within a decade.

Now consider the top 400 U.S. income-earners — a far more exclusive club than the top 1 percent. Between 1992 and 2013, 72 percent of the top 400 retained that title for no more than a year. Over 97 percent retained it for no more than a decade.

HumanProgress.org advisory board member Mark Perry put it well in his recent blog post on this subject:

Whenever we hear commentary about the top or bottom income quintiles, or the top or bottom X% of Americans by income (or the Top 400 taxpayers), a common assumption is that those are static, closed, private clubs with very little dynamic turnover. …

But economic reality is very different — people move up and down the income quintiles and percentile groups throughout their careers and lives.

What if we look at economic mobility in terms of accumulated wealth, instead of just annual income (as the latter tends to fluctuate more)?

The Forbes 400 lists the wealthiest Americans by total estimated net worth, regardless of their income during any given year. Over 71 percent of Forbes 400 listees — and their heirs — lost their top 400 status between 1982 and 2014.

So, the next time you find yourself discussing the very richest Americans, whether by wealth or income, keep in mind the extraordinarily high rate of turnover among them.

And even if you never become one of the 11.1 percent of Americans who fleetingly find themselves in the “top 1 percent” of US income-earners, you’re still quite possibly part of the global top 1 percent.

On Tuesday, it was announced that over seventeen million new vehicles were sold in 2015, the highest it’s ever been in United States history.

While the media claims that this record has been reached because of drastic improvements to the US economy, they are once again failing to account for the central factor: credit expansion.

When interest rates are kept artificially low, individuals are misled into spending more than they otherwise would. In hindsight, they discover that their judgment errors wreaked havoc on their financial well-being.

This is a lesson that the country should have learned from the Subprime Crisis of 2008. Excessive credit creation led too many individuals to buy homes, build homes, and invest in the housing industry. This surge in artificial demand temporarily spiked prices, resulting in over four million foreclosed homes and the killing of over nine million US jobs.

Instead of learning from the mistakes that sent shock waves throughout most of the planet, the Federal Reserve has continued with its expansionist policies. Since 2009, the money supply has increased by four trillion, while the federal funds rate has remained at or near zero percent. Consequently, the housing bubble has been replaced with several other bubbles, including one in the automotive industry.

Automotive companies have taken advantage of the cheap borrowing costs, increasing vehicle production by over 100 percent since 2009:

In order to generate more vehicle purchases, these companies have incentivized consumers with hot, hard-to-resist offers, similar to the infamous “liar loans” and “no-money down” loans of the 2008 recession. Dealerships have increased spending on sales incentives by 14 percent since last year alone, and the banners in their shops now proudly proclaim their acceptance of any and all loan applications — “No Credit. Bad Credit. All Credit. 100 Percent Approval.” As a result, auto loans have increased by nearly $80 billion since 2009, many of which have been given to individuals with far-from-stellar credit scores. Today, almost 20 percent of all auto loans are given to individuals with credit scores below 620:

Not only are more auto loans being originated, but they are also increasing in duration. The average loan term is now sixty-seven months (that’s 5.58 years) for new cars and sixty-two (that’s 5.16 years) months for used cars. Both are record numbers.

Average transaction prices for new and used cars are also at their record highs. Used car prices have increased by nearly 25 percent since 2009, while new car prices have increased by over 15 percent. Part of this has to do with the increasing demand for cars generated by the upsurge in auto loans. The main reason, however, is that consumers — taking advantage of the accessibility of cheap credit — are purchasing more expensive body styles. This follows the housing bubble trend, when the median size of a newly built single-family home rose to 2,272 square feet at the start of 2007.

We all know the end result of the Great Recession — prices soared, millions of houses were foreclosed, and unemployment surged. Demand for homes then plummeted, and home prices ultimately dropped by 20 percent each month.

The auto bubble has yet to burst, but its negative effects are already starting to gradually appear. For one, delinquencies on car loans have increased by nearly 120 percent, from just over 1 percent in 2010 to 2.62 percent in 2014. Since cars rapidly depreciate in value, this number is projected to spike. By the time these six, seven, and eight year no-money down loans are due to be paid in full, many of these vehicles won’t be worth paying off anymore — maintenance and loan costs will start exceeding the value of the cars.

According to the Center for Responsible Lending, one in every six title-loan borrowers is already facing repossession fees. If defaults sharply increase in the coming years as projected, the market will become flooded with used cars, and their prices will, with near certainty, fall to a significant degree.

At a time when labor force participation is at its lowest level since 1977 — at a time when real wages are rising less than they have since at least the 1980s — it is imperative that the Federal Reserve stop misleading individuals into making irrational investments. The economy is simply too frail to continue weathering these endless business cycles. Economists, politicians, and the general populace need to start learning from their economic history so they can begin recognizing that favoring debt over thrift isn’t beneficial to the country’s financial well-being. Failure to do so will simply lead to more bubbles, more malinvestment, and more economic headaches in the years to come.

The dozens of different programs that form our tangled welfare system often impose high effective marginal tax rates that make it harder for low-income people to transition out of these programs and lift of those programs and into the middle class. As the people in these programs enter the workforce, get a promotion, or work more hours, they can lose a significant portion of those earnings through reduced benefits and increased taxes. A new report from the Congressional Budget Office (CBO) illustrates this predicament: many households hovering around the poverty level face steeper effective marginal tax rates than even the highest earners. These prohibitively high tax rates can discourage work and limit their prospects, ultimately making them less likely to escape poverty.

Marginal Tax Rates at the Median and 90th Percentiles by Earnings Group, 2016

CBO’s analysis looks at the range of effective marginal tax rates households face at different levels of income. The median marginal tax rate for households just above the poverty level is almost 34 percent, the highest for any income level. Some households that receive larger benefits or higher state taxes have even higher effective rates: 10 percent of households just above the poverty line face a marginal rate higher than 65 percent. For each additional dollar earned in this range, these households would lose almost two-thirds to taxes or lost benefits. The comparable rate for the highest earners, households above 400 percent of the poverty level, is only 43.4 percent. If anything this analysis might understate how steep the effective marginal rates are for some households. CBO only considers the combined effect of income taxes, payroll taxes, SNAP and ACA exchange subsidies, so households that participate in other programs like TANF or housing assistance could face even higher rates. These results mirror some of Cato’s pastwork investigating the issues and trade-offs involved with these welfare programs.

The nature of the welfare system contributes to the prevalence of these poverty traps. A House and Ways Human Resources Subcommittee recently held a hearing on issue and released a chart illustrating the complex, labyrinthine nature of the welfare system.

Click on the image for a full-sized view.

New programs were grafted onto the existing system over time, each intended to address a perceived problem afflicting people in poverty, but they can interact in ways that can deter people from striving to create a better life for their families. That’s part of the reason the status quo system, which the Government Accountability Office estimates spends $742 billion at the federal level each year, has achieved such lackluster results to date.

While these shortcomings would seem to indicate that the welfare system is in need of reform, this tangled web has proved resistant to change. One of the last major reforms happened in 1996, when Temporary Assistance for Needy Families (TANF) replaced Aid to Families with Dependent Children (AFDC). Even that reform only addressed one strand of the dozens that make up our tangled system, so while it might have improved that one aspect the larger flaws with the welfare system as a whole have to some extent continued unabated. Even within this one strand there has been little discussion of reform in the past two decades, TANF hasn’t even been properly reauthorized since the Deficit Reduction Act of 2005, it is usually thrown into short-term continuing resolutions or broader omnibus appropriations acts that do not incorporate any meaningful attempts to address the program’s problems. Absent comprehensive, the flawed current system will continue to fall short even as the government funnels hundreds of billions of dollars into it each year.

If the federal government is going to finance a welfare system, it should foster an environment that encourages work and makes it easier for participants to transition out of these programs as they strive to create a better life. The current system falls far short in that regard and needs comprehensive reforms.

Charles Hughes is a research associate at the Cato Institute, where he focuses on federal budget policy, poverty, entitlement reform, and general economics. Originally from Texas, Hughes joined Cato in 2011 after graduating from the University of Chicago with degrees in Economics and Public Policy.

I know I’m not alone. Consider the justified roasting that Bernie Sanders got on social media for wondering why student loans come with interest rates of 6 or 8 or 10 percent while a mortgage can be taken out for only 3 percent. (The answer, of course, is that a mortgage has collateral in the form of a house, so it is a lower-risk loan to the lender than a student loan, which has no collateral and therefore requires a higher interest rate to cover the higher risk.)

When it comes to economic ignorance, libertarians are quick to repeat Murray Rothbard’s famous observation on the subject:

It is no crime to be ignorant of economics, which is, after all, a specialized discipline and one that most people consider to be a “dismal science.” But it is totally irresponsible to have a loud and vociferous opinion on economic subjects while remaining in this state of ignorance.

Economic ignorance comes in different forms, and some types of economic ignorance are less excusable than others. But the most important implication of Rothbard’s point is that the worst sort of economic ignorance is ignorance about your economic ignorance. There are varying degrees of blameworthiness for not knowing certain things about economics, but what is always unacceptable is not to recognize that you may not know enough to be speaking with authority, nor to understand the limits of economic knowledge.

Let’s explore three different types of economic ignorance before we return to the pervasive problem of not knowing what you don’t know.

1. What Isn’t Debated

Let’s start with the least excusable type of economic ignorance: not knowing agreed-upon theories or results in economics. There may not be a lot of these, but there are more than nonspecialists sometimes believe. Bernie Sanders’s inability to understand why uncollateralized loans have higher interest rates would fall into this category, as this is an agreed-upon claim in financial economics. Donald Trump’s bashing of free trade (and Sanders’s, too) would be another example, as the idea that free trade benefits the trading countries on the whole and over time is another strongly agreed-upon result in economics.

Trump and Sanders, and plenty of others, who make claims about economics, but who remain ignorant of basic teachings such as these, should be seen as highly blameworthy for that ignorance. But the deeper failing of many who make such errors is that they are ignorant of their ignorance. Often, they don’t even know that there are agreed-upon results in economics of which they are unaware.

2. Interpreting the Data

A second type of economic ignorance that is, in my view, less blameworthy is ignorance of economic data. As Rothbard observed, economics is a specialized discipline, and nonspecialists can’t be expected to know all the relevant theories and facts. There are a lot of economic data out there to be searched through, and often those data require careful statistical interpretation to be easily applied to questions of public policy. Economic data sources also require theoretical interpretation. Data do not speak for themselves — they must be integrated into a story of cause and effect through the framework of economic theory.

That said, in the world of the Internet, a lot of basic economic data are available and not that hard to find. The problem is that many people believe that certain empirical facts are true and don’t see the need to verify them by actually checking the data. For example, Bernie Sanders recently claimed that Americans are routinely working 50- and 60-hour workweeks. No doubt some Americans are, but the long-term direction of the average workweek is down, with the current average being about 34 hours per week. Longer lives and fewer working years between school and retirement have also meant a reduction in lifetime working hours and an increase in leisure time for the average American. These data are easily available at a variety of websites.

The problem of statistical interpretation can be seen with data on economic inequality, where people wrongly take static snapshots of the shares of national income held by the rich and poor to be evidence of the decline of the poor’s standard of living or their ability to move up and out of poverty.

People who wish to opine on such matters can, again, be forgiven for not knowing all the data in a specialized discipline, but if they choose to engage with the topic, they should be aware of their own limitations, including their ability to interpret the data they are discussing.

3. Different Schools of Thought

The third type of economic ignorance, and the least blameworthy, is ignorance of the multiple perspectives within the discipline of economics. There are multiple schools of thought in economics, and many empirical questions and historical facts have a variety of explanations. So a movie like The Big Short that clearly suggests that the financial crisis and Great Recession were caused by a lack of regulation might be persuasive to people who have never heard an alternative explanation that blames the combination of Federal Reserve policy and misguided government intervention in the housing market for the problems. One can make similar points about the Great Depression and the difference between Hayekian and Keynesian explanations of business cycles more generally.

These issues involving schools of thought are excellent examples of Rothbard’s point about the specialized nature of economics and what the nonspecialist can and cannot be expected to know. It is, in fact, unrealistic to expect nonexperts to know all of the arguments by the various schools of thought.

Combining Ignorance and Arrogance

What is missing from all of these types of economic ignorance — and what is often missing from knowledgeable economists themselves — is what we might call “epistemic humility,” or a willingness to admit how little we know. Noneconomists are often unable to recognize how little they know about economics, and economists are often unable to admit how little they know about the economy.

Real economic “expertise” is not just mastery of theories and facts. It is a deeper understanding of the variety of interpretations of those theories and facts and humility in the face of our limits in applying that knowledge in attempting to manage an economy. The smartest economists are the ones who know the limits of economic expertise.

Commentators with opinions on economic matters, whether presidential candidates or Facebook friends, could, at the very least, indicate that they may have biases or blind spots that lead to uses of data or interpretive frameworks with which experts might disagree.

The worst type of economic ignorance is the type of ignorance that is the worst in all fields: being ignorant of your own ignorance.

Venezuela is currently going through its worst crisis in history, replete with an endless list of interesting problems. Foremost among these are severe shortages in even the most basic of necessities. Economists have used these shortages as textbook examples to illustrate the pernicious effects of price controls.

Few people, however, are aware that many of the country’s problems are caused by a complex monetary arrangement that makes use of four different exchange rates simultaneously. The result is that Venezuela can either be extremely cheap, or unbearably expensive, depending on the rate used.

Monetary chaos began in 2003 when the late President Hugo Chavez imposed currency controls to stem capital flight after an oil strike. At the time, one US dollar could fetch 1.6 Venezuelan bolivars. Today, barely ten years later, that same dollar can buy 172 bolivars, a devaluation of over 99 percent! Of course, that is in the official (i.e., government regulated) market. On the black market, the exchange rate is currently nearly 900 bolivars to the US dollar. That is, if you can find anyone selling dollars, or more importantly, looking to buy the badly tarnished Venezuelan currency.

This devaluation is in and of itself a large problem, both for consumers who must deal with high degrees of price inflation and for businesses that must undergo long-term capital planning decisions with a constantly moving monetary unit. However, it is the volatility of the exchange rate caused by the government’s continuous changes to currency restrictions and official rates that is proving the most cumbersome problem.

A Very Complex System of Exchange Rates

Currently there are four exchange rates: First is the official one, called CENCOEX, and which charges 6.30 bolivars to the dollar. It is only intended for the importation of food and medicine.

The next two exchange rates are SICAD I (12 bolivars per dollar) and SICAD 2 (50 bolivars per dollar); they assign dollars to enterprises that import all other types of goods. Because of the fact that US dollars are limited, coupons are auctioned only sporadically; usually weekly in the case of SICAD 1 and daily for SICAD 2. However, due to the economic crisis, no dollars have been allocated for these foreign exchange transactions and there hasn’t been an auction since August 18, 2015. As of November 2015, the Venezuelan government held only $16 billion in foreign exchange reserves, the lowest level in over ten years, and an amount that will dry up completely in four years time at the current rate of depletion.

The last and newest exchange rate is the SIMADI, currently at 200 bolivars per dollar. This rate is reserved for the purchase and sale of foreign currency to individuals and businesses.

There are many problems in Venezuela as a result of this complex system. The most obvious is the near impossibility to actually get assigned to these rates due to the complex bureaucratic process one must navigate to apply for them. In response to these difficulties, Venezuelans must rely on the black market to meet their demands for foreign currency. Therefore, people naturally rely on the black market rate, which although it is much less advantageous (at 900 vs. anywhere from 6.3 to 200 bolivars per dollar on the “official” market), at least offers the possibility to procure the much needed foreign exchange.

Corruption, which is a main characteristic of Venezuela’s political regime, is another problem derived from this complex monetary system. Officials within the government and those connected to it have taken advantage of their positions of power and influence to mismanage the money assigned for other, productive and necessary, institutions. Thus, well-connected individuals obtain US dollars through the legal channels and then sell them on the black market at a higher price. (This activity is one of the only ways to consistently earn high levels of profits in the beleaguered Venezuelan economy, and is only available to those privileged few who are connected to the proper government officials.)

This point is especially important when studying the vast array of shortages. The embezzlement of foreign currency intended for importing basic goods, e.g., foreign exchange reserved for the CENCOEX and SICAD exchange rates, leave legitimate businessmen with no options to obtain legally the necessary currencies to import goods. Owing to the rapidly depreciating bolivar, US dollars are hoarded as a means of savings, thus further exacerbating the foreign exchange shortage for importers. As a consequence, imports are unable to be paid for, leading to shortages on top of those already caused by extensive and damaging price controls.

The Poor Suffer the Most

These problems affect directly all citizens, but are especially pernicious to lower-income individuals. Many suppliers will only sell what few goods they have for US dollars, eschewing accepting bolivars in the payment of their wares. Black market currency sellers set up shop outside supermarkets to accommodate this phenomenon, but it must be noted that only the upper-middle and higher income earners are able to afford to pay the black market rate. The result is that the lower-income segment of Venezuelan society, those who price and currency controls are supposedly helping, are not able to obtain the currency necessary to buy simple goods and services (and the wealthy can only do so at a high price).

Although the business community demands to be paid in US dollars this harms lower-income individuals unduly and is a completely rational response. If businesses kept selling their scarce supply of goods at the official rate their shelves would deplete faster than they already do. Venezuelans earn income at the official rate of 6.30 bolivars to the US dollar while businesses must pay a much higher rate in order to import goods. This difference must be accounted for by stores asking for prices commensurate with what they must pay to stock their shelves.

The complex exchange rate system in Venezuela is not only a good example of unnecessary government meddling in the economy, but also explains why a corrupt political regime has been able to retain power for so long despite more than a decade of hardship imposed on the country. The use of several exchange rates has made it easy for the Chávez and Maduro governments and their followers to make enormous profits by embezzling the money assigned to the business community and individuals. By doing so, they have completely devalued the bolivar and impoverished what was once one of the richest countries in the world.

Emiliana Disilvestro studies international business at Saint Louis University at its Madrid campus.

David Howden is Chair of the Department of Business and Economics and professor of economics at St. Louis University’s Madrid Campus, and Academic Vice President of the Ludwig von Mises Institute of Canada.

Senators Ted Cruz (R-Texas) and Mike Lee (R-Utah) have just introduced a bill that would implement an idea that I have long championed: making drugs, devices, and biologics that are approved in other developed countries also approved for sale in the United States.

Highlights of the “Reciprocity Ensures Streamlined Use of Lifesaving Treatments Act (S. 2388), or the RESULT Act,” include:

Amending the Food, Drug and Cosmetic Act to allow for reciprocal approval of drugs, devices and biologics from foreign sponsors in certain trusted, developed countries including EU member countries, Israel, Australia, Canada and Japan.

Encouraging the FDA to expeditiously review life-saving drug and device applications, this legislation would provide the FDA with a 30-day window to approve or deny a sponsor’s application….

The HHS Secretary is instructed to approve a drug, device or biologic if the FDA confirms the product is:

Lawfully approved for sale in one of the listed countries;

Not a banned device by current FDA standards;

There is a public health or unmet medical need for the product.

If a promising application for a life-saving drug is declined Congress is granted the authority to disapprove of a denied application and override an FDA decision with a majority vote via a joint resolution.

We continue to lose far too many of our loved ones to the “invisible graveyard,” as economist Alex Tabarrok has described: lives that could have been saved but for a bureaucratic barrier that rejects medical cures and innovation…

The bill I am introducing takes the first step to reverse this trend. It provides for reciprocal drug approval, so that cures and medical devices that are already approved in other countries can more expeditiously come to the U.S.

Fortunately, the gruelingly long workweek described by Sanders is not the norm. In fact, leisure time has been on the rise. In 1950, an average U.S. worker worked 1,984 hours a year, or about 38 hours a week. In 2015, an average American worker worked 1,767 hours, or about 34 hours a week.

That means that the average U.S. worker had 217 more hours for leisure or other pursuits in 2015 than in 1950. That is about 9 days of extra time.

The 50-hour workweek described by Sanders is more common in China, where the average worker worked 2,432 hours in 2015, or around 47 hours a week.

I’m a fan of the LGBT center on the campus where I teach. It offers a space where gay, lesbian, bisexual, and transgender students can be among students, faculty, and staff without fear of harassment, bullying, or negative judgment. There, they do not have to worry about passing (pretending to be straight) or covering (having to signal to others that they are still “normal” despite who they are).

But do you know what spaces like this are not? Diverse.

Or rather, they are not diverse in the types of attitudes permitted to exist there. One cannot, say, believe that homosexuality is a sin and feel welcome at an LGBT center. One cannot believe that transgender people are mentally ill and find LGBT centers to be congenial.

This lack of diversity is not wrong; it is by design and has a good purpose. A safe space is one where people with certain identities that don’t fit in elsewhere can find safety through homogeneity and solidarity.

We don’t need to dismiss either ideal to recognize that a space’s safety and its diversity will be inversely related. The more you have of one, the less you must have of the other.

But you can have spaces and contexts that allow for either ideal, or varying degrees of compromise between them — unless activists succeed in their current quest to convert entire universities into safe spaces.

The Yale case is well known by now. Erika Christakis, a lecturer in early child development, voiced concern in an email to Yale students and residence-life folks urging them to rethink the university’s heavy-handed approach to advising students on which Halloween costumes to avoid. Her note ignited controversy and protest on campus — with some even calling for Christakis’s resignation — because the possibility of students wearing offensive Halloween costumes makes the campus a potentially unsafe space.

In another recent example, the University of Missouri has been experiencing protests regarding alleged racist speech and treatment of minority students. During one of these protests, a journalist trying to cover the event was evidently shouted down and intimidated because his (journalistic) presence at the protest allegedly threatened the protesters’ safe space. (Think about how odd it is to describe the site of a vigorous protest as a safe space).

One journalist described a video of the events as follows:

In the video of Tim Tai trying to carry out his ESPN assignment, I see the most vivid example yet of activists twisting the concept of “safe space” in a most confounding way. They have one lone student surrounded. They’re forcibly preventing him from exercising a civil right. At various points, they intimidate him. Ultimately, they physically push him. But all the while, they are operating on the premise, or carrying on the pretense, that he is making them unsafe.

If people who regularly find their campuses (or other places) to be inhospitable, it may do them good to have social spaces where they are assured some level of relief, probably with people they are comfortable with. But think about what that means for diversity.

Increasing diversity is another aspiration at universities and other organizations, but safe spaces demand that the people in the space have a certain degree of homogeneity. For Yale to be a safe space, the university must disallow a diversity of Halloween costumes.

Why did the Missouri protesters suggest that Tai’s presence threatened to turn their protest into an unsafe space? Because there was a possibility that the narrative this journalist would construct might not be one the homogeneous protesters would approve of. Tai threatened the homogeneity and solidarity of the protest.

Let’s go back to the example of LGBT centers. That these students have somewhere they can go where they do not feel pressures to hide or “tone down” their identities is important, and any society that promotes freedom of association will have many such centers, whether official or not. But the only way for an entire university to become a safe space for LGBT students is to sacrifice diversity by, for example, demanding that religious students not believe (at least openly) that homosexuality is sinful. The converse is also true: LGBT centers could no longer function as safe spaces for LGBT students if they became sites of more diversity, where those religious students could regularly voice their beliefs.

Diversity cannot thrive in a world that is one big safe space.

Why? Because diversity means difference. Difference means that people will invariably see things in different ways, and we will sometimes anger each other. It’s not a bug, but a feature. To eliminate the possibility that some of us could deeply offend others of us would be to require everyone to live only in ways acceptable to all.

Diversity means a world where black-power advocates can live openly and in ways that anger white people — and where white-power advocates can live openly and thus anger black people. A world of diversity is one where people with different tastes, comfort levels, and senses of humor can wear Halloween costumes that may offend others.

The best resolution is to allow people on college campuses and elsewhere to create safe spaces. If we believe others’ Halloween costumes may deeply offend us, or that people may say derogatory and racist things to us, we can go to one of those spaces. But leave the university as a diverse space — don’t force it to become a safe space.

Diversity and emotional safety are values at odds with each other. They can coexist in tension, but the expansion of one can only come at the expense of the other.

Kevin Currie-Knight teaches in East Carolina University’s Department of Special Education, Foundations, and Research. He is a member of the FEE Faculty Network.

Washington, DC, has a juvenile curfew law. Anyone “under the age of 17 cannot remain in or on a street, park or other outdoor public place, in a vehicle or on the premises of any establishment within the District of Columbia during curfew hours.” There are exemptions for juveniles accompanied by a parent and for travel for jobs (no detours allowed.)

Curfew laws keep some juveniles off the streets during curfew hours, but which ones? The criminals seem the least likely to be deterred, and with fewer people on the street, perhaps the criminals are emboldened.

The DC curfew switches from midnight to 11 pm on Sept 1 of every year. In a working paper, Jennifer L. Doleac and Jillian Carr test the effect of DCs juvenile curfew on gun violence by looking at the number of gunshots heard in the 11pm to midnight “switching hour” just before and just after Sept 1. From a summary:

The September 1 change provides a clean natural experiment. If curfews reduce gun violence, then when the curfew shifts to 11:00 p.m. rather than midnight, gunfire between 11:00 p.m. and midnight should go down. Does it?

Just the opposite. Using data on gunfire incidents from ShotSpotter (acoustic gunshot sensors that cover the most violent neighborhoods in D.C.), we find that after the curfew switches from midnight to 11:00 p.m., the number of gunshot incidents increases by 150 percent during the 11:00 p.m. hour.

This amounts to 7 additional gunfire incidents city-wide per week, during that hour alone. Jane Jacobs was right: the deterrent effect of having lots of people out on the streets is powerful. This makes juvenile curfew policies counter-productive.

The use of ShotSpotter data is innovative and avoids some problems with issues of police enforcement. Calls to 911, however, don’t show the same pattern as the ShotSpotter data, which is worrying.

I’d also like to see more information on the proposed mechanism. Is it really the case that significantly fewer people are out on the streets at say 11:30 pm after the curfew has been lowered to 11 pm than when the curfew was set at midnight? The curfew only directly affects people under 17 and, as noted above, there are quite a few exemptions. Also what are the ages of those typically arrested on the basis of ShotSpotter alerts?

By the way, on a typical day in DC there are almost 15 gunfire incidents heard by ShotSpotter (data here, the authors report 8 but that may be from a restricted sample). A lot of gunfire is heard around a handful of schools. The ShotSpotter system is quite accurate. Although it misses some shots it distinguishes shots from car backfires better than people do. I also found this note from the Washington Post amusing, in a frightening way:

About a third of detected gunshot incidents in the city happen on New Year’s Eve or around July 4. Officials explain the high rate as celebratory gunfire.